Automatic Capping Machines and Bottle Stability

Automatic Capping Machines and Bottle Stability

Though many different types of automatic capping machines exist, they must all have one thing in common.  In some way, shape or form, the packaging machinery used to cap bottles must keep containers stabile in order to achieve consistent and reliable seals.  The devices used to achieve the stability can differ from machine to machine, but two general methods are commonly used for bottle stability.

The first comes in the form of gripper belts and a stabilizer bar.  This method is almost always seen on an inline spindle capping machine, as well as several other inline capping machines.  As the bottles move down the conveyor and enter the capping machine, gripper belts are positioned to guide the bottles through the capping process.  These moving belts hold the bottle steady while also propelling it through and past the spinning disks that will tighten the cap.  Working in conjunction with the gripper belts on many occasions is a stabilizer bar that will keep the cap in position through the process as well.  The stabilizer bar simply applies a small amount of pressure to the top of the cap to ensure that the cap does not tip, tilt or fall off while torque is being applied to create the seal.

Other capping machines, such as snap cappers and spindle, snap combination cappers, will also use gripper belts to guide the bottles through the capping process.  However, in some cases, the set-up of the sealing apparatus will not require a stabilizer bar.  For example, a snap capping machine may use a belt to snap down the lid.  Once the lid or cap is placed, the snap belt itself stabilizes the top while securing it in place.  

The second method to stabilize bottles while being capped requires the use of a starwheel or starwheel indexing.  A starwheel is basically a disk with a certain number of pockets cut out to hold bottles.  An automatic chuck capper will often use a starwheel to stabilize bottles.  Once in the pocket, the starwheel will turn and position the bottle to receive a cap.  Once the cap is placed on the bottle, the starwheel rotates once again to position the bottle under a capping head.  The capping head then descends and applies torque to tighten the cap.  ROPP capping machines will also utilize a starwheel a majority of the time.

While these two solutions will work for a large majority of packagers, other methods do exist for creating bottle stability when applying a lid or other seal.  In some cases, small or uniquely shaped containers may require a "puck" to move the container through the capping process.  In packaging terminology, a puck is simply a device that is used to transport unstable bottles through the packaging process.  Consider a vial or tube with a rounded bottom.  Gripper belts, stabilizer bars and starwheels are not going to solve the stability problem in such a case.  The tube can be placed into a rectangular puck with a flat bottom to stabilize the container and allow for the movement of the tube through the packaging line, including the capping machine.

Cap type and size as well as the package itself will help determine the ideal capping machine - and the ideal solution for bottle stability - for any given project.  Whether using a standard method for stability or some custom application, there always exists a solution to allow for consistent, reliable bottle closures.